1. Field of the Invention
The present invention relates to liquid discharging apparatuses.
2. Description of the Related Art
Recent liquid containers attached to liquid discharging apparatuses include electrically erasable and programmable read-only memories (EEPROMs) so as to control, for example, the amount of liquid being consumed. Since the EEPROMs serving as information storage portions can store information without being supplied with power, information on the amount of liquid being stored or being consumed can be retained even when the EEPROMs are detached from the liquid discharging apparatuses. However, when the electrical connection is cut while the EEPROMs are in the process of storing information, the information to be retained may be damaged. To avoid this, Japanese Patent Laid-Open Nos. 2001-162833 and 2003-266674, for example, describe methods for preventing electrical disconnection during the process of storing information in EEPROMs.
According to Japanese Patent Laid-Open No. 2001-162833, time required for the process of storing information in EEPROMs is secured by setting a liquid container to be temporarily undetachable when a user attempts to detach the liquid container. As an example of a liquid discharging apparatus using an off-carriage liquid container, Japanese Patent Laid-Open No. 2001-162833 describes a liquid discharging apparatus having a two-stage holder cover. A user cannot detach the liquid container from the apparatus until he/she opens a second holder cover after opening a first holder cover. Storage of information can be finished before the user opens the second holder cover and detaches the liquid container by starting the process of information storage when it is determined that the first holder cover is opened.
Japanese Patent Laid-Open No. 2003-266674 describes a liquid cartridge fixed in position by a positioning supporting unit. FIG. 7A illustrates a lever 154 positioned such that a first end 154a thereof is located at the uppermost position, and FIG. 7B illustrates the lever 154 positioned such that the first end 154a is located at the lowermost position. The lever 154 can move as can a crank, and when the first end 154a is located at the uppermost position, a limit switch 155, which is switched on or off in accordance with the contact position with a guide surface 154c of the lever 154, is turned off. In this state, information cannot be stored. At this moment, the liquid container can be detached since a cam 159 is separated from a fitting claw 153b. On the other hand, when the lever 154 is positioned such that the first end 154a is located at the lowermost position, the limit switch 155 is turned on by the guide surface 154c. In this state, information can be stored. At this moment, the cam 159 pushes the fitting claw 153b such that the liquid container cannot be detached. In this manner, a user cannot detach the liquid container without moving the first end of the lever 154 from the lowermost position to the uppermost position, and information can be stored while the first end of the lever 154 is moved.
In the case of a large liquid discharging apparatus that prints on large recording media, the liquid discharging apparatus can include an additional auxiliary liquid container inside the apparatus. Recording can be continued for a certain period of time even when a main liquid container is not attached to the apparatus by storing a certain amount of liquid supplied from the main liquid container in the auxiliary liquid container. That is, the main liquid container can be replaced without stopping the recording operation. With the above-described structure having the auxiliary liquid container, the interior of the liquid container is pressurized using a pump such that liquid is pushed out (supply by pressure), or the liquid is sucked from the liquid container using a pump (supply by suction).
However, when it is assumed that the liquid container, having the structure described in Japanese Patent Laid-Open No. 2001-162833 or 2003-266674, which is in use is detached from the apparatus during recording, an error may be generated between the actual amount of liquid being stored in the liquid container and information on the amount of liquid being stored written in the information storage portion of the liquid container. That is, in the case of the known structures, the liquid container is detached after the information on the amount of liquid remaining in the liquid container is stored in the information storage portion. Since the supply port remains connected to the liquid discharging apparatus even after the information storage is finished, the pressure for liquid supply continues to be applied to the liquid container, and liquid continues to be supplied to the head. This may cause an error between the actual amount of liquid being stored in the liquid container and information on the amount of liquid being stored written in the information storage portion of the liquid container, and the amount of liquid being stored may not be correctly obtained.